Identification Of Risk Factors And Construction And Validation Of A Risk Prediction Model For Systemic Lupus Erythematosus Patients With Initial Intestinal Symptoms

BackgroundSystemic lupus erythematosus(SLE)is one of common chronic and complex autoimmune disorders which may affect any organ or system,including the gastrointestinal tract.Gastrointestinal symptoms are common in SLE,mainly due to immunosuppressive therapies or infections.However,the intestinal symptoms due to active disease of SLE are relatively rare and most of them are atypical,resulting to the misdiagnosis and delayed diagnosis.Notably,gastrointestinal vasculitis and thrombosis may lead to intestinal ischemia perforation,and infarction,which may require surgical intervention or even be life-threatening if not treated promptly with immunosuppressive therapy.However,to date,data of intestinal involvement as initial symptoms in SLE are still rare and most of them are case reports.Therefore,we conducted a single-center,retrospective study to explore the risk factors of SLE with intestinal symptoms as the initial manifestation.ObjectiveTo explore the risk factors of SLE with intestinal symptoms as the initial manifestation,so as to raise the awareness of the disease and help clinicians make early and accurate diagnosis to improve the prognosis of the patients.MethodData of 195 patients with SLE admitted to the First Affiliated Hospital of Zhengzhou University for the first time from January 2013 to August 2020 were retrospectively collected.The patients were divided into two groups according to initial intestinal symptoms,including 58 patients as case group with intestinal symptoms as the initial manifestation,and 137 patients as control group without intestinal symptoms.Clinical data,imaging information,symptoms of different systems and organs,liver function,kidney function and antinuclear antibody spectrum were compared between the two groups.The independent-sample t test,Mann-Whitney U test,and Chi-square test were used for statistical analysis.Logistic regression analysis was used to establish a risk predictive model for SLE patients with intestinal symptoms as the initial manifestation,and receiver operating characteristic(ROC)curve and Hosmer-Lemeshow goodness of fit test were used to evaluate the predictive value of the model.In addition,data of 78 SLE patients from the First Affiliated Hospital of Zhengzhou University from September 2020 to December 2021 were collected as the validation set(including 24 patients with initial intestinal symptoms and 54 patients without intestinal symptoms)to evaluate the predictive value of the model.Results1.Among the 195 SLE patients,58 patients(29.7%)were diagnosed with SLE with initial intestinal symptoms while 137(70.3%)without.Compared with the control group,more patients in the case group with initial intestinal symptoms suffered from intestinal edema or thickening,pyeloureterectasis,polyserositis,ascites,renal involvement and hematological involvement,while fewer patients had fever,muscle involvement,and joint involvement Besides,patients with intestinal symptoms as the initial manifestation had lower levels of C3,C4,and albumin(Alb)than patients without intestinal manifestations.[82.8%(48/58)vs 11.7%(16/137),51.7%(30/58)vs 3.6%(5/137),77.6%(45/58)vs 24.1%(33/137),69.0%(40/58)vs 14.6%(20/137),48.3%(28/58)vs 27.7%(38/137),50.0%(29/58)vs 27.7%(38/137),31.0%(18/58)vs 65.0%(89/137),3.4%(2/58)vs 27.7%(38/137),15.5%(9/58)vs 66.4%(91/137),0.48(0.38,0.60)g/L vs 0.75(0.41,0.96)g/L,0.09(0.06,0.15)g/L vs 0.14(0.08,0.22)g/L,29.30±5.53g/L vs 33.84±7.27g/L]the differences are statistically significant(χ2=93.374、63.948、48.595、56.542、7.677、8.955、18.943、14.744、42.267,Z=-4.240、一3.485,t=-4.255;P<0.05).2.Multivariate logistic regression analysis revealed that lower level of C3[odds ratios(OR)=0.147,95%confidence interval(CI):0.039-0.555,P=0.005]and lower level of Alb(OR=0.941,95%CI:0.893-0.992,P=0.023)were independent risk factors of SLE with intestinal symptoms as the initial manifestation.3.A prediction model was established as p=1/(1+e-Y),where Y=2.233-1.920×complement C3(g/L)-0.610×Alb(g/L),to predict the risk of SLE with intestinal symptoms as the initial manifestation p is the probability of predicting the SLE with initial intestinal symptoms.4.The area under the curve(AUC)of the ROC curve was 0.730(95%CI:0.660-0.801,P<0.001).The results of Hosmer-Lemeshow goodness-of-fit test(χ2=11.813,P=0.160),indicated that the model had a good calibration ability.5.The validation set verified the predictive value of the model.Patients were diagnosed as SLE with initial intestinal manifestation when p≥0.250 and the results showed that the sensitivity,specificity and overall accuracy of the prediction model were 70.8%(17/24),77.7%(42/54)and 75.6%(59/78),respectively.ConclusionIntestinal symptoms are a common complication of SLE.In some SLE patients,the intestinal tract is acted as the first symptom,and the symptoms are hidden,so it is easy to be missed and misdiagnosed in the process of clinical diagnosis and treatment.When imaging shows intestinal edema or thickening,ureteropelvic dilatation or biochemical indicators indicate low complement C3 and low Alb,one should be alert to the possibility of SLE.Early identification of SLE with intestinal symptoms as the first manifestation is extremely important,because early individualized treatment can significantly improve patient outcomes.